4.4Base Peak,Molecular Ions,Fragment Ions and Metastable Ions78
4.4.1Base Peak78
4.4.2Molecular Ions79
4.4.3Fragment Ions79
4.4.4Metastable Ions79
4.5Recognition of the Molecular Ion Peak80
4.6Determination of a Molecular Formula81
4.7Fragmentation 83
4.7.1Representation of Fragmentation Processes83
4.7.2Simple Cleavage83
4.8Rearrangements85
4.9Fragmentation Modes of Various Classes of Organic Compounds86
4.9.1Hydrocarbons86
4.9.2Hydroxy Compounds89
4.9.3Ethers92
4.9.4Ketones93
4.9.5Aldehydes94
4.9.6Carboxylic Acids94
4.9.7Carboxylic Esters95
4.9.8Amines96
4.9.9Amides98
References98
Problems99
Chapter 5 Nuclear Magnetic Resonance Spectroscopy101
5.1Introductions of Nuclear Magnetic Resonance101
5.2Principal of Nuclear Magnetic Resonance103
5.31H NMR Spectroscopy105
5.3.1Acquisition of 1H NMR Spectroscopy105
5.3.2Chemical Shift108
5.3.3Integration Signal Strength111
5.3.4Factors Influencing the Chemical Shifts112
5.3.5Coupling Constants Spin-Spin Interactions116
5.413C NMR Spectroscopy122
5.4.1Broadband Decoupled 13C Spectrum122
5.4.2DEPT 13C NMR Spectrum126
5.5Two-Dimensional NMR126
5.6Solid State NMR128
5.6.1Introduction of Solid State NMR128
5.6.2Application of Solid-State NMR in Pharmaceutical Polymorphism130
References132
Problems133
Chapter 6 Single Crystal X-ray Crystallography136
6.1Introductions of X-ray Crystallography136
6.2Crystal and Amorphous Solid137
6.2.1Single Crystal, Non-crystal, Twin Crystal and Powder Crystal139
6.2.2Crystal Properties140
6.2.3Symmetry in Crystals140
6.2.4Crystal Growth144
6.3Discovery and Properties of X-ray148
6.3.1Discovery of X-ray148
6.3.2X-ray Properties150
6.4Diffraction of X-ray by Crystals150
6.4.1Laue Experiment150
6.4.2Brag Equation151
6.4.3Principle of Single Crystal X-ray Diffraction153
6.4.4X-ray Diffraction Data Collection154
6.5Calculations of Electronic Density Map156
6.6The Procedures for Crystal Structure Determination158
6.7Applications of Single Crystal X-ray Crystallography in Drug Discovery and Development160
6.8Summary165
References165
Problems165
Chapter 7 Integrated Spectroscopic Analysis169
7.1Introduction169
7.2General Procedures169
7.3Examples170
7.3.1Compound A170
7.3.2Compound B173
7.3.3Compound C176
7.3.4Compound D180
References185
Problems185
Answer to Problems189
Index198
內容試閱:
The structural characterization of organic compounds is a means of understanding the materials at the molecular level.Structures determine the functions of materials.So structural analysis is an important part of organic chemistry.In the past, the chemical method was mainly used to determine the structure of organic compounds; however, it took a long time.For example, though morphine was isolated from opium in 1805 by a German scientist Friedrich, its structure was identified in 1952 by classic chemical analysis.In 1820, quinine was isolated from cinchona by French researchers Pierre and Joseph; however, extensive and classic chemical studies led to elucidation of the structure of quinine in 1944.The shortcomings of traditional chemical methods include less accurate, a long time, and a large amount of materials several grams.
With the development of modern sciences, techniques, e.g.Ultraviolet-visible spectroscopy UV, infrared spectroscopy IR, and nuclear magnetic resonance NMR based on the interactions between molecules with individual electromagnetic wave were developed.Another spectrum, mass spectrometry, though it is a fragmentation spectrum of the molecule, it can provide molecular weight and fragmentation information, and assist the structural determination of organic compound.These modern spectral methods provide very accurate and rich structural information.It takes less time and only need a small amount of materials about 10 mg to finish the structure determinations.
In most books of organic structural analysis, single-crystal X-ray diffraction is not included.X-ray crystallography is a technique used for determining the three dimensional structures of compounds through the diffraction of X-ray by single crystals.Though it is not a typical spectral method, it is widely used in structural analysis, especially structures with new carbon skeletons.Furthermore, it can provide detailed conformation and configuration information.Thus, this approach is also included in this book.
The book provides comprehensive knowledge of structural analysis of organic compounds.It is divided into seven parts.The first part is the general introduction of spectral analysis, the second to the sixth parts introduce the principles and applications of UV-Vis Spectroscopy, Infrared Spectroscopy, Mass Spectrometry, Nuclear Magnetic Resonance and Single Crystal X-ray Diffraction, and the last chapter is comprehensive analysis of organic compounds.
Thought of compiling
1)During the past several decades, techniques including Ultraviolet-visible spectroscopy UV, Infrared spectroscopy IR, Mass spectrometry MS, nuclear magnetic resonance NMR and X-ray diffraction X-ray have been used as the dominant methods for the characterization of chemical structures of organic compounds.The aim of this book is to provide a comprehensive and contemporary introduction to the principals of these diverse and fascinating techniques and their applications in structural analysis.All readers will be trained in interpreting individual spectra and sets of spectra obtained by different methods.Its convenient and rapid to elucidate most of structures of organic compounds using the complementary information from the five types of approaches.
2)Each chapter is accompanied by a large number of exercises and the corresponding answers are listed in the appendix.The practice of these exercises can deepen the understanding of the knowledge in each chapter.
3 Key references were provided so that the readers can further explore the terminology ad concept listed in this book.
4)This book is mainly in English.However, all the key terms of terminology in annotated in Chinese, and the captions of the Figures and Tables are put in both English and Chinese.It is convenient for the beginners to understand the contents of this book.
Target readership
1)The book is very informative, and is suitable for undergraduates and graduate students majoring in pharmacy, chemistry and chemical engineering.It can also be used by teachers engaged in pharmacy and chemistry.
2)This book provides a detailed introduction of the major technologies in the field of organic structural analysis in English.It is very useful for the students planning to further their studies in overseas and to publish papers regarding organic structural analysis in international journals.
Suggestions when using this textbook
This textbook provides a comprehensive introduction to UV-VIS, IR, MS, NMR 1H NMR, 13C NMR, 2D, solid state and X-ray diffraction.First, students are required to learn the basic principles of these technologies, to grasp the structural information that each technology can provide, and to learn to use a combination of these techniques to identify structures of unknown compounds.Among them, the structural information provided by each technology is the focus, and the basic principle is most difficult part.Secondly, the content of the spectral analysis course is relatively abstract.It is difficult for students to understand the principle of each technique and the corresponding instruments.All beginners will feel boring and difficult to understand.It is recommended that readers actively participate in the corresponding experimental classes or go to the corresponding lab when studying this textbook.Through visiting and learning in the experimental class or lab, the readers will gain a basic idea about the generation process of these spectra, and establish a reasonable link between theory and practice.Again, the textbook should be read and prepared before class.During the class, the readers need to listen to the teachers explanation carefully.After the class, the readers should review the textbook again with the help of the teachers courseware.
Learning method
The textbook Structural Analysis of Organic Compounds includes many contents.In order to achieve the expected learning results, readers are recommended to use the following methods:
1 Step by step
This textbook is divided into seven chapters.When you study each chapter, first look at the catalogue and find out what is included in this chapter.Then open the textbook and quickly browse the contents of this chapter, and then read carefully to master the contents.
2 Consolidate the foundation
The textbook Structural Analysis of Organic Compounds is difficult.If there is no relevant foundation, it is difficult to understand the principals, especially some professional terminologies, and it will affect the progress of learning.Therefore, before the textbook is previewed, readers should be given appropriate basic learning according to their own situation, especially the knowledge of organic chemistry.
3 Keep writing notes
It is good to keep writing notes when you read.Notes can help readers to grasp the key points, understand the content, and greatly improve learning efficiency.
4 Do exercises
During the course of learning this course, you can use the exercises in the textbook to test after the completion of a chapter.
This textbook is used for teaching and learning only.Due to the rush of time and limited editorial level, the mistakes are inevitable, please inform me when you have corrections.